EP2641934A1 - Silicon composition with improved mechanical properties - Google Patents

Abstract

Silicone composition comprises at least one addition or condensation curable polydiorganosiloxane with a viscosity of 10-500000 MPa at 23[deg] C, at least one cross-linking agent for the polydiorganosiloxane, at least one organotin compound, at least one complex of an element selected from groups IV, X, XII, XIII, and XV of the periodic system of elements, at least one silica acid with a Brunauer, Emmet, and Teller (BET) surface of 50-300 m 2>/g, and at least one chalk with a BET surface of 10-25 m 2>/g and an average particle size (d 5 0) of 10-1000 nm. Independent claims are included for the following: (1) increasing the tear propagation resistance of a silicone composition involving: combining a filler material with the silicone composite, where the filler material contains at least one silica acid with a BET surface of 50-300 m 2>/g and at least one chalk with a BET surface of 10-25 m 2>/g and an average particle size (d 5 0) of 10-1000 nm, together with a catalyst or accelerator system containing at least one organotin compound and at least one complex of an element selected from the groups IV, X, XII, XIII, and XV of the periodic system of elements; and (2) a cured silicone composition obtainable from single-component silicone composition by reaction with moisture; or obtainable from a two-component silicone composition by mixing component A with component B.

Description

Technical area

The present invention relates to the field of silicone compositions, as used in particular as adhesives and sealants.

State of the art

Silicone compositions have been known for some time and are used in particular as adhesives and sealants in various applications. Both single-component, moisture-curing silicone compositions and room-temperature crosslinking, two-component silicone compositions are widely used.

Since silicone compositions are often used in the construction sector, they must meet special requirements with regard to their properties, in particular the mechanical properties. For example, in Switzerland such regulations are issued by the Federal Office for Civil Protection. Among other things, there are certain demands on the tear strength of silicone composition, it being known that straight silicone compositions have relatively low tear resistance.

EP0649879 discloses silicone compositions containing a specific filler combination of hexamethyldisilazane surface-modified precipitated silica and stearate-coated precipitated calcium carbonate and a tin catalyst. By using these very specific fillers, the tear resistance of the silicone composition can be improved.

The disadvantage of compositions according to EP0649879 This is because these specific fillers make expensive and thus are expensive.

Presentation of the invention

It is therefore an object of the present invention to provide a silicone composition with improved tear propagation resistance, which can also be achieved with common low-cost fillers.

Surprisingly, it has been found that silicone compositions according to claim 1 solve this problem.
By using a catalyst or accelerator system of an organotin compound and at least one complex of an element selected from Groups 4, 10, 12, 13 and 15 of the Periodic Table of the Elements, it is possible to increase the tear resistance of the silicone composition using a filler combination at least one silica having a BET surface area of from 50 to 300 m ² / g and at least one chalk having a BET surface area of from 10 to 25 m ² / g and an average particle size d 50 of from 10 to 1000 nm. The fillers used need not be pretreated or coated in complex processes.

Further aspects of the invention are the subject of further independent claims. Particularly preferred embodiments of the invention are the subject of the dependent claims.

Ways to carry out the invention

• mindestens ein additions- oder kondensationsvernetzbares Polydiorganosiloxan mit einer Viskosität von 10 bis 500'000 mPa·s bei einer Temperatur von 23°C,
• mindestens einen Vernetzer für das Polydiorganosiloxan,
• mindestens eine zinnorganische Verbindung,
• mindestens einen Komplex eines Elements ausgewählt aus den Gruppen 4, 10, 12, 13 und 15 des Periodensystems der Elemente,
• mindestens eine Kieselsäure mit einer BET-Oberfläche von 50 bis 300 m²/g, sowie
• mindestens eine Kreide mit einer BET-Oberfläche von 10 bis 25 m²/g und einer mittleren Teilchengrösse d50 von 10 bis 1000 nm.

The present invention relates to a silicone composition comprising

• at least one addition- or condensation-crosslinkable polydiorganosiloxane having a viscosity of from 10 to 500,000 mPa · s at a temperature of 23 ° C.,
• at least one crosslinker for the polydiorganosiloxane,
• at least one organotin compound,
• at least one complex of an element selected from Groups 4, 10, 12, 13 and 15 of the Periodic Table of the Elements,
• at least one silica having a BET surface area of 50 to 300 m ² / g, and
• at least one chalk having a BET surface area of 10 to 25 m ² / g and an average particle size d 50 of 10 to 1000 nm.

Substance names beginning with "poly", such as, for example, polyol, refer in the present document to substances which formally contain two or more of the functional groups occurring in their name per molecule.
The term "polymer" in the present document comprises on the one hand a collective of chemically uniform, but differing in terms of degree of polymerization, molecular weight and chain length macromolecules, which was prepared by a polyreaction (polymerization, polyaddition, polycondensation). On the other hand, the term also encompasses derivatives of such a collective of macromolecules from polyreactions, compounds which have been obtained by reactions, such as additions or substitutions, of functional groups on given macromolecules and which may be chemically uniform or chemically nonuniform. The term also includes so-called prepolymers, that is, reactive oligomeric pre-adducts whose functional groups are involved in the construction of macromolecules.

The polydiorganosiloxane in the silicone composition according to the invention is in particular a vinyl-terminated polydiorganosiloxane or a polydiorganosiloxane P of the formula (I).

The radicals R ¹ , R ² and R ³ independently of one another are linear or branched, monovalent hydrocarbon radicals having 1 to 12 C atoms which optionally contain one or more heteroatoms, and optionally one or more CC multiple bonds and / or optionally cycloaliphatic and or aromatic portions.

In particular, the radicals R ¹ and R ^{2 are} alkyl radicals having 1 to 5, in particular having 1 to 3, carbon atoms, preferably methyl groups. The radicals R ³ independently of one another are in particular phenyl, vinyl or methyl groups.
The radicals R ⁴ are each independently hydroxyl or alkoxy, acetoxy or Ketoximgruppen each having 1 to 13 carbon atoms, which optionally one or more heteroatoms, and optionally one or more CC multiple bonds and / or optionally cycloaliphatic and / or have aromatic components.
The index p stands for a value of 0, 1 or 2, in particular for 0 or 1. Furthermore, the index m is selected so that the polydiorganosiloxane P at a temperature of 23 ° C has a viscosity of 10 to 500,000 mPa · s , in particular from 1000 to 250,000 mPa · s.

Preferably, the polydiorganosiloxane is a condensation crosslinkable polydiorganosiloxane.

If the radicals R ^{4 are} ketoxime groups, they are preferably ketoxime groups each having 1 to 13 C atoms and the index p is in particular a value of 0.

Preferred ketoxime groups are dialkylketoxime groups whose alkyl groups each have 1 to 6 carbon atoms. Preferably, the two alkyl groups of the dialkylketoxime groups independently of one another are methyl, ethyl, n-propyl, iso-propyl, n-butyl or isobutyl groups. Particularly preferred are those cases in which one alkyl group of the dialkyl ketoxime is a methyl group and the other alkyl group of the dialkyl ketoxime is a methyl, ethyl or iso-butyl group. Most preferably, the ketoxime group is an ethylmethylketoxime group.

The radicals R ⁴ are preferably hydroxyl groups and the index p is a value of 2.

Suitable polydiorganosiloxanes, as shown in particular in formula (I), are known and commercially available. The preparation of such polydiorganosiloxanes is carried out in a known manner, such as described in US 4,962,152 ,

Furthermore, the present composition comprises at least one crosslinker for the polydiorganosiloxane.

When the polydiorganosiloxane is an addition-curable polydiorganosiloxane, especially a vinyl-terminated polydiorganosiloxane, the crosslinker for the polydiorganosiloxane is a hydrosiloxane, a derivative thereof or a mixture of several hydrosiloxanes or derivatives, the crosslinker having on average at least two SiH groups per molecule having. Suitable hydrosiloxanes have between 0.01 mmol / g and 2 mol / g H-atoms, based on the weight of the hydrosiloxane. Furthermore, suitable hydrosiloxanes have a viscosity of between 0.1 mPa.s and 150,000 mPa.s at 25 ° C.
Particularly suitable crosslinkers are compounds of the formula (II)

The radicals R ¹ and R ² have been described previously.
The radical R ⁵ is an oxygen atom or a monovalent hydrocarbon radical having 1 to 30 C atoms, which optionally has one or more heteroatoms, and optionally one or more CC multiple bonds and / or optionally cycloaliphatic and / or aromatic moieties.
n and q stand independently for values from 0 to 20.
Particularly suitable crosslinkers are selected from the group consisting of poly (dimethylsiloxane-co-methylhydrosiloxane),
Tris (dimethylsilyloxy) phenylsilane, bis (dimethylsilyloxy) diphenylsilane,

Polyphenyl (dimethylhydrosiloxy) siloxane, methylhydrosiloxane phenylmethylsiloxane copolymer, methylhydrosiloxane-alkylmethylsiloxane copolymer, polyalkylhydrosiloxane, methylhydrosiloxane-diphenylsiloxane-alkylmethylsiloxane copolymer, polyphenylmethylsiloxane methylhydrosiloxane, and cyclic species such as tetramethylcyclotetrasiloxane and pentamethylcyclopentasiloxane.

Dabei steht der Rest R⁶ unabhängig voneinander für einen linearen oder verzweigten, Kohlenwasserstoffrest mit 1 bis 12 C-Atomen, welcher gegebenenfalls ein oder mehrere Heteroatome, und gegebenenfalls eine oder mehrere C-C-Mehrfachbindungen und/oder gegebenenfalls cycloaliphatische und/oder aromatische Anteile aufweist.
X steht für ein Heteroatom, insbesondere für O oder N. Ist X gleich N, so trägt dieses N neben R⁷ zusätzlich ein Wasserstoffatom oder eine Alkylgruppe, insbesondere eine Alkylgruppe mit 1 bis 5, insbesondere mit 1 bis 3, C-Atomen, bevorzugt eine Methylgruppe. Der Rest R⁷ steht unabhängig voneinander für ein Wasserstoffatom, oder für einen Alkylrest mit 1 bis 12 C-Atomen, oder für einen Ketiminrest mit 1 bis 13 C-Atomen, oder für einen Acylrest mit 1 bis 12 C-Atomen. Insbesondere steht der Rest R⁷ für einen Alkylrest mit 1 bis 5, insbesondere 1 bis 3, C-Atomen, bevorzugt für eine Methyl- oder Ethylgruppe.
Der Index s steht für einen Wert von 0 bis 4, wobei falls s für einen Wert von 3 oder 4 steht, mindestens s-2 Reste R⁶ jeweils mindestens eine mit den reaktiven Gruppen des Polydiorganosiloxans P reaktive, insbesondere kondensierbare, Gruppe, also beispielsweise eine Hydroxylgruppe aufweisen. Insbesondere steht s für einen Wert von 0, 1 oder 2, bevorzugt für einen Wert von 1. Der Index t steht für einen Wert von 1, 2 oder 3, insbesondere 1 oder 2. Für die Wahl des Silans der Formel (III) als Vernetzer für Polydiorganosiloxane können unterschiedliche Anforderungen an die Siliconzusammensetzung ausschlaggebend sein. Einerseits spielt die Reaktivität des Silans eine wichtige Rolle, wobei grundsätzlich höherreaktive Silane bevorzugt werden. Andererseits können auch toxikologische Gründe für die Wahl des Vernetzers ausschlaggebend sein. Beispielsweise ist deshalb Tetraethoxysilan als Vernetzer gegenüber Tetramethoxysilan bevorzugt.When the polydiorganosiloxane is a condensation-curable polydiorganosiloxane, in particular a polydiorganosiloxane P of the formula (I) as described above, the crosslinker for the polydiorganosiloxane is in particular a silane of the formula (III).

In this case, the radical R ⁶ independently of one another is a linear or branched, hydrocarbon radical having 1 to 12 C atoms, which optionally has one or more heteroatoms, and optionally one or more CC multiple bonds and / or optionally cycloaliphatic and / or aromatic moieties.
X is a heteroatom, in particular O or N. If X is N, this N additionally carries, in addition to R ⁷ , a hydrogen atom or an alkyl group, in particular an alkyl group having 1 to 5, in particular having 1 to 3, C atoms, preferably a methyl group. The radical R ⁷ is independently of one another a hydrogen atom, or an alkyl radical having 1 to 12 C atoms, or a ketimine radical having 1 to 13 C atoms, or an acyl radical having 1 to 12 C atoms. In particular, the radical R ^{7 is} an alkyl radical having 1 to 5, in particular 1 to 3, carbon atoms, preferably a methyl or ethyl group.
The subscript s stands for a value of 0 to 4, where if s stands for a value of 3 or 4, at least s-2 radicals R ^{6 are} each at least one reactive with the reactive groups of the polydiorganosiloxane P , in particular condensable group, ie for example have a hydroxyl group. In particular, s stands for a value of 0, 1 or 2, preferably for a value of 1. The index t stands for a value of 1, 2 or 3, in particular 1 or 2. For the choice of the silane of the formula (III) as crosslinker for polydiorganosiloxanes, different requirements for the silicone composition may be decisive. On the one hand, the reactivity of the silane plays an important role, with generally more highly reactive silanes being preferred. On the other hand, toxicological reasons for the choice of the crosslinker may also be decisive. For example, therefore, tetraethoxysilane is preferred as a crosslinker over tetramethoxysilane.

Examples of suitable silanes of the formula (III) are methyltrimethoxysilane, chloromethyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, methyltripropoxysilane, phenyltripropoxysilane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, 2-aminoethyl-3 -aminopropyltrimethoxysilane, 2-aminoethyl-3-aminopropyltriethoxysilane, N-phenylaminomethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, bis (N-methylacetamido) methylethoxysilane, tris (methylethylketoximo) methylsilane, tris (methylethylketoximo) vinylsilane, tris (methylethylketoximo) -phenylsilane, N , N-bis (triethoxysilylpropyl) amine, N, N-bis (trimethoxysilylpropyl) amine, or 1,2-bis (triethoxysilyl) ethane.
The silane of the formula (III) is particularly preferably vinyltrimethoxysilane or tetraethoxysilane or a mixture thereof.

Furthermore, the silanes may already partially (a part of all R ⁷ = H) or fully hydrolyzed (all R ⁷ = H) are present. Due to the greatly increased reactivity of partially or completely hydrolyzed silanes, their use as crosslinkers may be advantageous. It is known to the person skilled in the art that the use of partially or completely hydrolyzed silanes can lead to the formation of oligomeric siloxanes, in particular of dimers and / or trimers, which are formed by condensation of hydrolyzed silanes. Accordingly, it is also possible to use oligomeric siloxanes as crosslinkers for the two-component silicone composition. For example, suitable oligomeric siloxanes are hexamethoxydisiloxane, hexaethoxydisiloxane, hexa-n-propoxydisiloxane, hexa-n-butoxydisiloxane, octaethoxytrisiloxane, octa-n-butoxytrisiloxane, and decaethoxytetrasiloxane.

Of course, as a crosslinker for the two-component silicone composition, any mixture of the aforementioned silanes can be used.

The proportion of the crosslinker for polydiorganosiloxanes is preferably from 0.1 to 15% by weight, in particular from 1 to 10% by weight, preferably from 2 to 5% by weight, of the total silicone composition.

Furthermore, the silicone composition according to the invention comprises at least one organotin compound.
Preferred organotin compounds are dialkyltin compounds, for example those selected from the group consisting of dimethyltin di-2-ethylhexanoate, dimethyltin dilaurate, di-n-butyltin diacetate, di-n-butyltin acetoacetonate, di-n-butyltin dioxide, di-n-butyltin di-2-ethylhexanoate , Di-n-butyltin dicaprylate, di-n-butyltin di-2,2-dimethyloctanoate, di-n-butyltin dilaurate, di-n-butyltin distearate, di-n-butyltin dimaleinate, di-n-butyltin dioleate, di-n-octyltin diacetate , Di-n-octyltin acetoacetonate, di-n-octyltin dioxide, di-n-octyltin di-2-ethylhexanoate, di-n-octyltin di-2,2-dimethyloctanoate, di-n-octyltin dimaleinate and di-n-octyltin dilaurate.

Of course, it is possible or in some cases even preferred to use mixtures of various organotin compounds.

The proportion of the organotin compound is preferably 0.001 to 1 wt .-%, in particular 0.005 to 0.1 wt .-%, of the total silicone composition.

The silicone composition according to the invention furthermore comprises at least one complex of an element selected from groups 4, 10, 12, 13 and 15 of the Periodic Table of the Elements.
In particular, it is a complex of boron, aluminum, antimony, bismuth, titanium, zirconium or zinc, preferably of titanium or zirconium.

Particularly preferred complexes, especially of titanium and zirconium, have ligands selected from the group consisting of alkoxy group, sulfonate group, carboxylate group, dialkyl phosphate group, dialkyl pyrophosphate group and acetylacetonate group, wherein all ligands may be identical or different from each other.
Particularly suitable alkoxy groups are so-called neoalkoxy substituents, for example a 2,2-bis ((allyloxy) methyl) butoxy substituent.
Particularly suitable sulfonic acids are aromatic sulfonic acids whose aromatic groups have been substituted by an alkyl group.
Carboxylates of fatty acids have proven particularly suitable as carboxylate groups. The preferred carboxylate are decanoate, stearate and isostearate.

In particular, the complex, in particular the titanate or the zirconate, has at least one polydentate ligand, also called chelate ligand. In particular, the multidentate ligand is a bidentate ligand.

The bidentate ligand is preferably a ligand of the formula (IV)

In this case, the radical R ^{21 is} a hydrogen atom or a linear or branched alkyl group having 1 to 8 C atoms, in particular a methyl group.
The radical R ²² represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 C atoms, which optionally has heteroatoms, in particular a hydrogen atom.
The radical R ²³ is a hydrogen atom or an alkyl group having 1 to 8, in particular having 1 to 3, carbon atoms or a linear or branched alkoxy group having 1 to 8, in particular having 1 to 3, carbon atoms.

The complex is preferably a titanate of the formula (V).

The radicals R ²¹ , R ²² and R ²³ have already been described above.
The radical R ²⁴ is a linear or branched alkyl radical having 1 to 20 C atoms, in particular an isobutyl or isopropyl radical.
n stands for a value of 1 or 2, in particular for 2.
Preferred are titanates of the formula (V), wherein the radical R ^{21 is} a methyl group, the radical R ^{22 is} a hydrogen atom, the radical R ^{23 is} a Methyl group or methoxy or ethoxy group and the radical R ^{24 is} an isobutyl or isopropyl radical.

Suitable titanates for example, under the trade names Tyzor ^® AA, GBA, GBO, AA-75, AA-65, AA-105, DC, BEAT, Ibay commercially available from Dorf Ketal or under the trade names Tytan ™ PBT, TET, X85 , TAA, ET, S2, S4 or S6 commercially available from Borica.
Suitable zirconates are, for example, under the trade name Tyzor ^® NBZ, NPZ, TEAZ, 212, 215, 217, 223 commercially available from Dorf Ketal or under the trade name K-Kat 4205 or K-Kat XC-6212 from King Industries. A suitable aluminate is available, for example, under the trade name K-Kat 5218 from King Industries. Suitable bismuthates are available, for example, under the trade name K-Kat 348 and K-Kat XC-8203 from King Industries. Of course, it is possible or in some cases even preferable to use mixtures of different complexes of one element selected from Groups 4, 10, 12, 13 and 15 of the Periodic Table of the Elements.

The proportion of complex is preferably 0.002 to 5 wt .-%, in particular 0.005 to 3 wt .-%, preferably 0.01 to 1.5 wt .-%, of the total silicone composition.

The organotin compound and the complex of an element selected from Groups 4, 10, 12, 13 and 15 of the Periodic Table of the Elements together form a catalyst or promoter system for the crosslinking of the polydiorganosiloxane.
Preferably, the proportion of the organotin compound and the at least one complex together 0.005 to 7 wt .-%, in particular 0.01 to 5 wt .-%, preferably 0.02 to 2 wt .-%, based on the total silicone composition.
The ratio of the organotin compound to the complex is preferably between 1:10 and 100: 1, in particular between 1: 1 and 80: 1, preferably between 5: 1 and 50: 1 and most preferably between 10: 1 and 30: 1.
The silicone composition according to the invention furthermore comprises at least one silica having a BET surface area of from 50 to 300 m ² / g, in particular from 100 to 250 m ² / g.
Suitable silicas are precipitated or pyrogenic silicas which may be surface-hydrophobized or which may be untreated, ie hydrophilic.
As hydrophobized silicas typically siliconized and / or silanized silicas are suitable, which then have a carbon content of 0.6 to 6.5 wt .-% based on the total weight of the silica. However, suitable silicic acids can also not be treated, ie they may be hydrophilic. It is also possible to use mixtures of different silicas.
The proportion of silica is preferably 1 to 35 wt .-%, in particular 3 and 30 wt .-%, preferably 5 and 25 wt .-%, particularly preferably 8 and 20 wt .-%, based on the total silicone composition.

Furthermore, the silicone composition according to the invention comprises at least one chalk having a BET surface area of 5 to 25 m ² / g and an average particle size d 50 of 10 to 1000 nm.
The specification of the particle size d50 refers to the fact that 50 wt .-% of the particles have a size which is equal to or less than the specified value. The particle size d50 can typically be determined by laser light scattering in accordance with the standard ISO 13320: 2009, for example with the CILAS 920 device from CILAS.

Suitable chalks are natural or precipitated chalks (calcium carbonates) which are in particular surface-treated, ie hydrophobic. The surface treatment can be carried out, for example, by treatment with fatty acids, in particular stearic acid, preferably with calcium stearate. Of course, mixtures of different chalks can be used.

The proportion of chalk is preferably 1 to 50 wt .-%, in particular 2 and 40 wt .-%, preferably 5 and 30 wt .-%, particularly preferably 7 and 25 wt .-%, based on the total silicone composition.

Silica and chalk are used as fillers in the silicone composition according to the invention. The fillers affect both the rheological properties of the uncured composition and the mechanical properties and surface finish of the cured composition.
A total amount of filler in the silicone composition is typically in the range of 10 to 70 wt%, more preferably 15 to 60 wt%, preferably 30 to 60 wt%.

The silicone composition according to the invention may optionally contain further constituents.
Such additional constituents are in particular plasticizers, further fillers, curing accelerators, pigments, adhesion promoters, processing aids, rheology modifiers, stabilizers, dyes, inhibitors, heat stabilizers, antistatics, flame retardants, biocides, waxes, leveling agents, thixotropic agents and other common raw materials and additives known to the person skilled in the art.
When using such optional constituents, it is advantageous to select all of the constituents which may be present in the silicone composition in such a way that the storage stability of the silicone composition is not adversely affected by the presence of such a constituent, that is to say that the composition has properties, especially the application and curing properties, not or only slightly changed during storage. This requires that reactions leading to chemical curing of the silicone composition described do not occur to a significant extent during storage. It is therefore particularly advantageous that said components contain no or at most traces of water or release during storage. Therefore, it may be useful to have certain ingredients to dry chemically or physically when mixed into the composition.

Suitable plasticizers for the silicone composition according to the invention are, in particular, trialkylsilyl-terminated polydialkylsiloxanes, in particular trimethylsilyl-terminated polydimethylsiloxanes. Preference is given to trimethylsilyl-terminated polydimethylsiloxanes having viscosities of from 1 to 10 000 mPa · s. Viscosities between 10 and 1000 mPa.s are particularly preferred. However, it is also possible to use trimethylsilyl-terminated polydimethylsiloxanes in which some of the methyl groups have been replaced by other organic groups such as, for example, phenyl, vinyl or trifluoropropyl. Although it is particularly preferred to use linear trimethylsilyl-terminated polydimethylsiloxanes as plasticizers, it is also possible to use those compounds which are branched. It is also possible, instead of the polysiloxane plasticizers, to use organic compounds, such as, for example, certain hydrocarbons or mixtures thereof, as plasticizers. Such hydrocarbons may be aromatic or aliphatic. In particular, care must be taken in the selection that these hydrocarbons have a low volatility and a sufficient compatibility with the other constituents of the silicone composition.
The proportion of the plasticizer is preferably from 2 to 15% by weight, in particular from 5 to 10% by weight, of the total silicone composition.

Particularly suitable as adhesion promoters are alkoxysilanes, which are preferably substituted by functional groups. The functional group is, for example, an aminopropyl, glycidoxypropyl or mercaptopropyl group. Preference is given to amino-functional groups. The alkoxy groups of such silanes are usually a methoxy or ethoxy group. Particularly preferred are aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane and 3-mercaptopropyltriethoxysilane. It is also possible to use a mixture of adhesion promoters. Other suitable adhesion promoters include, for example, amino-functional alkylsilsesquioxanes, such as amino-functional methylsilsesquioxane or aminofunctional propylsilsesquioxane, alkoxylated alkyleneamines, in particular ethoxylated and / or propoxylated alkylenediamines, and further, in particular substituted, oligomers, polymers or copolymers based on polyalkylene glycols.
It is clear to the person skilled in the art that, when using silanes as adhesion promoters, it is possible that they may be partially or fully hydrolyzed, depending on the conditions, for example in the case of moisture. Furthermore, it is known to the person skilled in the art that, in the presence of such partially or completely hydrolyzed silanes, condensation reactions can lead to the formation of oligomeric siloxanes, in particular to dimers and / or trimers.

The proportion of the adhesion promoter is preferably from 0.1 to 15% by weight, in particular from 1 to 10% by weight, preferably from 1 to 5% by weight, of the total two-component silicone composition.

The silicone composition according to the invention can be formed as a one-component or as a two-component composition.
When it is a one-part silicone composition, it is especially designed to crosslink under the influence of heat or moisture. Most preferred one-part silicone compositions crosslink at room temperature under the influence of moisture, in particular humidity, crosslinking being effected by condensation of silanol groups to form siloxane bonds.

In particular, when the silicone composition is a two-part composition, it is a two-part silicone composition consisting of a component A and a component B , wherein the polydiorganosiloxane, crosslinker, and organotin compound catalyst and accelerator system are complexed to the two components be divided so that the crosslinking reaction only begins during or after the mixing of the two components.

• das mindestens eine additions- oder kondensationsvernetzbare Polydiorganosiloxan mit einer Viskosität von 10 bis 500'000 mPa·s bei einer Temperatur von 23°C,
• die mindestens eine Kieselsäure mit einer BET-Oberfläche von 50 bis 300 m²/g, sowie
• die mindestens eine Kreide mit einer BET-Oberfläche von 10 bis 25 m²/g und einer mittleren Teilchengrösse d50 von 10 bis 1000 nm;

und einer Komponente B umfassend

• den mindestens einen Vernetzer für das Polydiorganosiloxan,
• die mindestens eine zinnorganische Verbindung,
• den mindestens einen Komplex eines Elements ausgewählt aus den Gruppen 4, 10, 12, 13 und 15 des Periodensystems der Elemente.

In particular, the two-part silicone composition is comprised of a component A.

• the at least one addition- or condensation-crosslinkable polydiorganosiloxane having a viscosity of from 10 to 500,000 mPa · s at a temperature of 23 ° C.,
• the at least one silica having a BET surface area of 50 to 300 m ² / g, and
• the at least one chalk having a BET surface area of 10 to 25 m ² / g and an average particle size d 50 of 10 to 1000 nm;

and a component B comprising

• the at least one crosslinker for the polydiorganosiloxane,
• the at least one organotin compound,
• the at least one complex of an element selected from Groups 4, 10, 12, 13 and 15 of the Periodic Table of the Elements.

Both component A and component B of the described two part silicone composition are prepared and stored with the exclusion of moisture. Separately, the two components are storage stable, that is, they can be stored in suitable packaging or assembly for a period of several months to one year and longer, without being subject to their application properties or their properties after curing in a for change their use to a relevant extent. Usually, the storage stability is determined by measuring the viscosity or the reactivity over time.

In the application of the two-component silicone composition, the components A and B, for example, by stirring, kneading, rolling or the like, but in particular via a static mixer, mixed together, resulting in the curing of the composition. The curing of the two-component silicone composition takes place in particular at room temperature.

If the silicone composition according to the invention is a two-component silicone composition, this is used in particular such that the weight ratio of component A to component B is 1 1: 1, in particular from 3: 1 to 15: 1, preferably from 10: 1 to 13: 1, is.

In the crosslinking of the silicone composition, the reaction reaction products of the condensation reaction are in particular also compounds of the formula HO-R ⁴ , where R ^{4 has} already been described above. Preferably, these by-products of the condensation reaction are compounds which affect neither the composition nor the substrate on which the composition is applied. Most preferably, the reaction product of formula HO-R ⁴ is a compound which readily volatilizes from the crosslinking or already crosslinked composition.

Furthermore, the present invention relates to the use of a silicone composition as described above as an adhesive, sealant, coating or casting compound.

In particular, the inventive silicone composition is suitable for bonding, sealing or coating substrates which are selected from the group consisting of concrete, mortar, brick, brick, ceramic, gypsum, natural stone such as granite or marble, glass, glass ceramic, metal or metal alloy such as aluminum , Steel, non-ferrous metal, galvanized metal, wood, plastic such as PVC, polycarbonate, polymethyl (meth) acrylate, polyester, epoxy resin, paint and varnish.

The silicone composition is preferably used in the construction sector, in particular in window and facade construction.

Furthermore, the present invention relates to a cured silicone composition obtainable from a one-component silicone composition as described above, in particular by reaction with moisture, or from a previously described two-component silicone composition by mixing component A with component B.

Furthermore, the present invention relates to the use of a filler combination comprising at least one silica having a BET surface area of 50 to 300 m ² / g and at least one chalk having a BET surface area of 10 to 25 m ² / g and an average particle size d50 of 10 to 1000 nm, together with a catalyst or accelerator system comprising at least one organotin compound and at least one complex of an element selected from Groups 4, 10, 12, 13 and 15 of the Periodic Table of the Elements, to increase the tear propagation resistance of silicone compositions.

It is a particular advantage of the present invention that it is now possible to formulate one-component and two-component silicone compositions having improved tear propagation resistance, using as fillers both natural and precipitated chalks which are present together with fumed and precipitated silicas which may be treated or untreated, be used. In contrast to the prior art, therefore, a significantly expanded range of fillers, in particular of particularly cost-effective, can be used.

Examples

In the following, exemplary embodiments are listed which are intended to explain the described invention in more detail. Of course, the invention is not limited to these described embodiments.

Preparation of silicone compositions Raw materials used:

OH-terminated PDMS of viscosity 50 Pa · s can be obtained under the trade name Polymer FD 50 from Wacker. OH-terminated PDMS of viscosity 80 mPa.s can be sold under the trade name Polymer OH 0.08 are obtained from the company Hanse Chemie. (CH ₃ ) ₃ Si-terminated PDMS of viscosity 100 mPa.s can be obtained under the trade name Silicone Oil AK 100 from Wacker. Vinyl-terminated PDMS of viscosity 20 Pa · s can be obtained under the trade name Flexosil ^® vinyl fluid 20,000 from the company BRB. Precipitated chalk can be obtained from the company Solvay under the trade names Winnofil ^® or Socal ^®. Natural chalk can be purchased under the trade names CALCILIT ^® or CALCIPLAST ^® from alpha calcite or under the trade name Carbital ^® by the company Imerys. Precipitated silicas are available under the trade name Sipernat ^® from Evonik or under the trade name zeosil ^® from Rhodia. Fumed silicas can be obtained from the company Wacker under the trade name Cabosil ^® by the company Cabot or under the trade name Aerosil ^® from Evonik or under the tradename HDK ^®. Titanium dioxide can be obtained under the trade name Kronos 2500 from Kronos. Silanes and siloxanes can be obtained from the company Wacker under the trade name Dynasylan ^® from Evonik or under the trade name Geniosil® ^®. Organotin compounds can be obtained under the trade name TIB ^Kat® from TIB. Titanates and zirconates can be obtained from the company DorfKetal under the trade name Tyzor ^®. Industrial carbon blacks may be obtained under the trade name Monarch ^® by Cabot or under the trade name Printex ^® from Orion Carbon.

As components A of the two-component silicone composition, the ingredients listed in Table 1 were mixed in the stated parts by weight in a dissolver at room temperature under an inert atmosphere and stirred until a macroscopically homogeneous paste was obtained.

As component B , the following components were prepared:

Component B1 : 34.7% by weight of a vinyl-terminated polydimethylsiloxane having a viscosity of 20,000 were used in a dissolver at room temperature mPa.s, 20 wt .-% tetraethyl orthosilicate, 6 wt .-% of an Ethylpolykieselsäureesters having an average molecular weight of about 800 g / mol, 6 wt .-% octyltrimethoxysilane, 2 wt .-% diisobutoxy-bisethylacetoacetatoorthotitanat, 1.3 wt. % Di-n-octyltin acetylacetonate, 10% by weight of 2-aminoethyl-3-aminopropyltriethoxysilane, 5% by weight of a hydrophobic, fumed silica having a BET surface area of 150 m ² / g and a carbon content of about 2.8% by weight. % which was predispersed in a vinyl-terminated polydimethylsiloxane and 15% by weight of an industrial carbon black having a BET surface area of 84 m ² / g and a primary particle size of 27 nm (% by weight, based in each case on the total mixture), mixed to one macroscopically homogeneous paste was obtained.

Component B2 : In a dissolver, at room temperature, 36% by weight of a vinyl-terminated polydimethylsiloxane having a viscosity of 20,000 mPa.s, 20% by weight of tetraethyl orthosilicate, 6% by weight of an ethylpoly-silicic acid ester having an average molecular weight of about 800 g / mol, 6% by weight of octyltrimethoxysilane, 2% by weight of di-n-octyltinacetylacetonate, 10% by weight of 2-aminoethyl-3-aminopropyltriethoxysilane, 5% by weight of a hydrophobic, fumed silica having a BET surface area of 150 m ² / g and a carbon content of about 2.8 wt .-%, which was pre-dispersed in a vinyl-terminated polydimethylsiloxane and 15 wt .-% of an industrial carbon black having a BET surface area of 84 m ² / g and a primary particle size of 27 nm (Wt .-% each based on the total mixture), mixed until a macroscopically homogeneous paste was obtained.

Component B3 : 34.7% by weight of a vinyl-terminated polydimethylsiloxane having a viscosity of 20,000 mPa.s, 20% by weight of tetraethylorthosilicate, 6% by weight of an ethylpoly-silicic acid ester having an average molar mass of about 800 were obtained in a dissolver at room temperature g / mol, 6% by weight octyltrimethoxysilane, 2% by weight tetra-n-propyl orthozirconate, 1.3% by weight di-n-octyltin acetylacetonate, 10% by weight 2-aminoethyl-3-aminopropyltriethoxysilane, 5% by weight % of a hydrophobic, fumed silica having a BET surface area of 150 m ² / g and a Carbon content of about 2.8 wt .-%, which was predispersed in a vinyl-terminated polydimethylsiloxane and 15 wt .-% of an industrial carbon black having a BET surface area of 84 m ² / g and a primary particle size of 27 nm (wt .-% in each case based on the total mixture) until a macroscopically homogeneous paste was obtained.

The prepared components A and B of the two-component silicone compositions were filled separately in cartridges, stored hermetically sealed and mixed directly before the application as shown in Table 1 in a weight ratio A: B of 13: 1 in a dissolver until a macroscopically homogeneous paste was obtained.

As a one-component silicone composition, the ingredients listed in Table 2 were mixed in the stated parts by weight in a dissolver at room temperature under an inert atmosphere and stirred until a macroscopically homogeneous paste was obtained.

The monocomponent silicone compositions prepared were filled directly into cartridges and stored hermetically sealed until application.

Description of the test methods

The method for determining the elongation at break and the tensile strength and the preparation of the required test specimens is described in ISO 527. Was measured at 23 ° C and 50% relative humidity on a test specimen Type 1 B (ISO 527-2) and with a pulling speed of 200 mm / min.
The method for the determination of tear propagation resistance as well as the preparation of the required test specimens is described in DIN ISO 34-1. Measurements were made on test specimens of type C. 1 2 3 4 5 6 7 8th 9 A OH-term. PDMS (viscosity: 50,000 mPa · s) 31 31 31 31 31 31 31 31 31 OH-term. PDMS (viscosity: 80 mPa · s) 0.6 0.5 0.5 0.5 0.5 0.5 0.5 0.6 0.5 (CH ₃ ) ₃ Si-term. PDMS (viscosity: 100 mPa · s) 39 39 39 39 39 39 39 39.2 39 Precipitated chalk treated with stearate (BET surface area: 15-24 m ² / g) 15.5 15.5 15.5 15.5 15.5 15.5 15.5 Natural chalk treated with stearate (BET surface area: 10 m ² / g, d 50 = 0.8 μm) 15.5 15.5 Hydrophobic fumed silica (BET surface area: 220 m ² / g, C content: 3-4% by weight) 13.8 Hydrophobic fumed silica (BET surface area: 160 m ² / g, C content: 2-4 wt.%) 13.8 13.8 13.8 13.8 13.8 Hydrophobic, precipitated silica (BET surface area: 125 m ² / g, HMDS-treated) 13.8 13.8 Hydrophilic precipitated silica (BET surface area: 165 m ² / g) 13.5 TiO ₂ (rutile) (oil number (ISO 787/5): 12) 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 B Weight ratio A: B = 13: 1 B1 B1 B2 B1 B2 B1 B2 B1 B3 Elongation at break (%) 327 364 330 395 361 317 300 568 355 Tensile strength [MPa] 1.6 1.4 1.1 1.6 1.5 1.1 1.0 2 1.2 Tearing resistance (Dye B) [N / mm] 12 8th 4 10 5 8th 3 12 9 Table 1: Two-part silicone compositions and results 10 11 (CH ₃ O) ₂ MeSi-term. PDMS (viscosity: 50 Pa · s) 35.3 35.3 (CH ₃ ) ₃ Si-term. PDMS (viscosity: 1000 mPa · s) 21 21 Methyl silicone resin, MeO-containing (viscosity: 20 mPa · s) 1.2 1.2 methyltrimethoxysilane 0.5 0.5 vinyltrimethoxysilane 1.5 1.5 Octylphosphonic acid + methyltrimethoxysilane (1: 0.75) 0.3 0.3 Di-iso-butoxy-bis -titant (ethylacetoacetato) 1.5 1.5 Di-octyl tin bisacetoacetonate 0.2 Natural chalk treated with stearate (BET surface area: 5 m ² / g, d 50 = 2 μm) 10 10.7 Hydrophobic fumed silica (BET surface area: 160 m ² / g, C content: 2-4 wt.%) 13.5 13 Precipitated chalk treated with stearate (BET surface area: 15-24 m ² / g) 15 15 Elongation at break (%) 550 450 Tensile strength [MPa] 2.3 2.2 Tearing resistance (Dye B) [N / mm] 18 7 Table 2: One-component silicone compositions and results

Claims (14)

Comprising silicone composition at least one addition- or condensation-crosslinkable polydiorganosiloxane having a viscosity of from 10 to 500,000 mPa · s at a temperature of 23 ° C., at least one crosslinker for the polydiorganosiloxane, at least one organotin compound, at least one complex of an element selected from Groups 4, 10, 12, 13 and 15 of the Periodic Table of the Elements, - At least one silica having a BET surface area of 50 to 300 m ² / g, and - At least one chalk with a BET surface area of 10 to 25 m ² / g and an average particle size d50 of 10 to 1000 nm. Silicone composition according to claim 1, characterized in that the polydiorganosiloxane is a vinyl-terminated polydiorganosiloxane or a polydiorganosiloxane P of the formula (I),

in which
the radicals R ¹ , R ² and R ³ independently of one another are linear or branched, monovalent hydrocarbon radicals having 1 to 12 C atoms which optionally contain one or more heteroatoms, and optionally one or more C-C multiple bonds and / or optionally cycloaliphatic and / or or have aromatic components,
the radicals R ⁴ independently of one another are hydroxyl groups or alkoxy, acetoxy or ketoxime groups having in each case 1 to 13 C atoms which may contain one or more heteroatoms, and optionally have one or more CC multiple bonds and / or optionally cycloaliphatic and / or aromatic moieties,
the index p is a value of 0, 1 or 2; and
the index m is chosen so that the polydiorganosiloxane P at a temperature of 23 ° C has a viscosity of 10 to 500,000 mPa · s. Silicone composition according to one of the preceding claims, characterized in that the at least one complex is a complex of boron, aluminum, antimony, bismuth, titanium, zirconium or zinc. Silicone composition according to claim 3, characterized in that the complex is a complex of titanium or zirconium. Silicone composition according to one of the preceding claims, characterized in that the proportion of the organotin compound and the at least one complex together 0.005 to 7 wt .-% based on the total silicone composition. Silicone composition according to one of the preceding claims, characterized in that the weight ratio of organotin compound to the complex is between 1:10 and 100: 1. Silicone composition according to one of the preceding claims, characterized in that the proportion of at least one silica having a BET surface area of 50 to 300 m ² / g 1 to 35 wt .-% based on the total silicone composition. Silicone composition according to one of the preceding claims, characterized in that the proportion of at least one chalk having a BET surface area of 10 to 25 m ² / g and a average particle size d50 from 10 to 1000 nm 1 to 50 wt .-% based on the total silicone composition. Silicone composition according to one of claims 1 to 8, characterized in that the composition is a one-component silicone composition. Silicone composition according to one of claims 1 to 8, characterized in that the composition is a two-component silicone composition comprising a component A. the at least one addition- or condensation-crosslinkable polydiorganosiloxane having a viscosity of from 10 to 500,000 mPa · s at a temperature of 23 ° C., - The at least one silica having a BET surface area of 50 to 300 m ² / g, and - The at least one chalk with a BET surface area of 10 to 25 m ² / g and an average particle size d50 of 10 to 1000 nm; and a component B comprising the at least one crosslinker for the polydiorganosiloxane, the at least one organotin compound, - The at least one complex of an element selected from Groups 4, 10, 12, 13 and 15 of the Periodic Table of the Elements. Silicone composition according to claim 10, characterized in that the weight ratio of component A to component B ≥ 1: 1, in particular from 3: 1 to 15: 1, preferably from 10: 1 to 13: 1. Use of a filler combination comprising at least one silica having a BET surface area of 50 to 300 m ² / g and at least one chalk having a BET surface area of 10 to 25 m ² / g and an average particle size d 50 of 10 to 1000 nm; together with a catalyst or accelerator system comprising at least one organotin compound and at least one complex of an element selected from Groups 4, 10, 12, 13 and 15 of the Periodic Table of the Elements,
for increasing the tear propagation resistance of silicone compositions. Use of a silicone composition according to one of claims 1 to 11 as an adhesive, sealant, coating or casting compound. A cured silicone composition obtainable from a one-component silicone composition according to claim 9, in particular by reaction with moisture, or from a two-component silicone composition according to claim 10 by mixing component A with component B.